This invention relates to an aperture electrode for controlling a supply operation of toners to an image support member to form a visible image on the image support member, and a method for manufacturing the aperture electrode used in a toner-jet type of recording apparatus.
Various kinds of image recording apparatuses utilize imaging material supply devices for supplying imaging material particles such as toners on support members. Of these devices, there has been particularly known a toner supply device in which charged toner particles are beforehand carried on a carry member and then electrostatically supplied on a support member disposed so as to confront the carry member in a gap therebetween. As this type of toner supply device, there has been proposed a toner supply device utilizing a plurality of control electrodes each having an aperture for passing toner particles therethrough. The control electrodes are placed between a toner carry member and a support member, and control flight of the toner particles through the apertures by applying image forming signals to the control electrodes to selectively charge the electrodes at a polarity opposite to the polarity of the toner particles and produce electric fields between the carry member and the control electrodes. The toner particles whose flight is controlled are positionally selectively coated on the support member to form a visible toner image corresponding to the image forming signals.
The aperture electrode of this type of toner supply device has been conventionally manufactured as follows. First, metal foils having approximately 10 .mu.m thickness are attached through adhesive layers to both surfaces of a polymer insulating film having approximately 100 .mu.m to form a laminate film having a multi-layer structure. Next, apertures such as holes or slits are formed by an excimer laser in such a manner as to be aligned with one another on the laminate film, and then the metal foil on one surface of the laminate film is patterned by a photoetching process to form plural control electrode layers around the apertures electrically independently of one another. The metal foil comprises stainless steel, copper or the like, and the polymer insulating film comprises polyester, polyimide, polyethylene or the like.
In the manufacturing method as described above, the adhesive is used to perform attachment between the insulating electrode and the aperture electrode and between the insulating electrode and a reference electrode layer which corresponds to the other metal foil layer on the other surface of the laminate film, and thus the adhesive is liable to leak into the apertures. Accordingly, in this type of aperture electrode, the toners are frequently adsorbed by the adhesive and clogged within the apertures, so that a toner coating is interrupted, and an image forming process is not performed.
Further, the aperture electrode is disposed in a gap having 1 mm or smaller distance between the toner carry member and a counter electrode confronting the toner carry member so as not to be contacted with both of the toner carry member and the counter electrode. On the other hand, since the aperture electrode comprises a multi-layer structure in which a polymer insulating film having approximately 100 .mu.m thickness and two metal foils having approximately 10 .mu.m are laminated, the laminate film has a low rigidity and thus an easily deformable property due to a minute external force. Therefore, the aperture electrode is liable to contact with the toner carry member or the counter electrode. This contact causes abnormal discharge between each of the aperture electrode and at least one of the toner carry member and the counter electrode because they are supplied with a high voltage to bring electrical noises, and thus the aperture electrode is liable to be malfunctionally operated.